Hello,

I have a new to me 'E' class racecar and was wondering what the best camber to run with 18" Hoosiers would be both front and rear.

The car is only for racing - no street driving. I want it to handle great and evenly wear the tires. The car has all race suspension and spherical bearings.

TIA..

Hoosier told me :
Front = -2 degrees
Rear = -1 degrees

I have heard some others run more negative.
But I do not want to destroy the tires like I did last year doing Kuhmo tests with too much negative camber....

This setup will be for MidOhio...

Norm Goldrich
Cincinnati, OH

 

Norm--I run my '89 at 2 1/2 degrees negative in the front and the Hoosier DOT tires have been wearing extremely well. It's also a nice compromise--since 3 degrees or more made for some rather squirrley braking--and 2 degrees or less resulted in an uneven contact patch. The Hoosiers do seem to be rather picky about the camber settings--much more so than others I've run--but I can't complain about the performance!

 

wasteg8, thanks for the reply.

What do you run the rear camber at ?

Norm

 

I run 17's with -3 on the left front side and -2.5 on the right front side. I also run -2.5 on both sides in the rear. I get tremendous wear out of a set of hoosier (usually 10+ DE days). Since I run the same tire/wheel combination at all corners (10" rim, 275 tire) I can also do a 4 way rotation which certainly helps.

My buddy runs 18's (245 front, 275 rear) and has -2.5 degrees on all 4 corners. Anything less than that and he burns through the outside edge of the tire very quickly.

 

944's do not need that much camber in the rear. -1.75 to - 2 depending in size of tire ... 2.5 in the rear is too much. -2.5 to -3.5 in the front. I have 17 inch hoosier 245, 275 on my race car I have - 3.1 and -1.75. If you are running goodyear slicks then you will need more camber .. but not with Hoosiers. It is very easy to tell by measuring the temp of the tires after a few hot laps.

944 turbo

 

Thanks guys.

I have 245 35 18 on front and 275 35 18 rears.

I just dont reallly want to destroy a couple of sets of tires doing setup testing like I did with Kuhmos...

So I appreciate the info...

Thanks,
Norm

 

ngoldrich, 944turbo gave you the real answer. Set your suspension and tire pressures to whatever concensus numbers you arrive at, but tune it for yourself with your driving style and at your track (I miss Mid Ohio) with tire temps. A tire temp guage will be the best $100-200 you ever spent to truly answer the question.

 

The whole idea behind setting static negative camber is to compensate for the body roll when cornering. This body roll causes a positive camber change on the outside tire. So the static negative camber you set is to counteract the positive camber when the body rolls.

No one has mentioned spring-rates and swaybars yet and those are a critical factors in determining optimum camber settings. Stiffer spring-rates and swaybars will require less static negative camber (because there's less body-roll).

Rather than going with others' optimum settings, which may or may not be the best settings for you, it would be better for you to find the optimum settings for your car yourself.

Get an infrared pyrometer so you can quickly take 12 temperature readings immediately after pulling off the track. Make a blank worksheet to list outside, middle, inside temperatures across the tread width for each tire. Then average the outside and inside. Here's the testing procedure:

TIRE PRESSURE
-If average of inside/outside temp. less than middle, lower tire pressure
-If average of inside/outside temp. more than middle, increase tire pressure

CAMBER - can't optimize until you get tire-pressures down
- if outside temp less than inside, decrease negative camber
- if outside temp more than inside, increase negative camber

Write down all your tire-pressure, temperatures, track conditions and alignment settings. You'll find that the optimum camber settings may not be identical front/rear or left/right, that's OK. And different tracks will actually require different alignment settings as well.

 

Danno.. THANK YOU once again. I've been battling Hoosier wear for a while and finally found a happy setting at -3, with my stock MO30s and camber plates. BUT, this season I went to the 968 MO30 sways, now I know to expect things to change. I'll frame your post and head to the track with a pyrometer in my back pocket. You probably just saved me $350. What a guy! Rennlist..the best $$ ever spent on a P car!

 

Danno, thanks.

I do have both and infrared and contact pyrometer. will use both. I normally do this on all my race cars (the others are prototypes (monocoques).

I really just wanted a safe starting point so I did not destroy the tires like I did last year with Kuhmos running too much camber.

The moral of the story was that I should have checked the tire temps after a couple of laps. Instead I ran about 8 laps an destroyed (blistered and chunked) the kuhmos. It probably would not have happened so quickly if they were shaved.

This car has externally adjustible resevoir JRZ shocks front & rear, km sway bars, spherical heim joints everywhere, fabcar arms. not sure of the spring rates since I just got the car.

however, a fantastic shop is setting it up - the one that ran it for the last few years, so I am sure it will be great.

I just had a bad taste after going through a couple of sets of tires in a weekend and a half. Of course, probably the most irritating is that I could have prevented it myself. Oh well, live and learn..

Thanks again for the info...

Norm

 

Danno--very good points! Everyone's set-up is different--and some tracks really require a lot of tweaking. Kinda OT--but as for the pyrometer--I've heard some argue that the old probe-type (like I use) is still preferred because it gets a truer reading than the infrared. Theory is the infrared reads mostly surface temp--while the probe goes deeper and therefore reads a more consistent mass. I've never done a side-by-side comparison--but there does seem to be some validity to this argument. Any thoughts?

 

Norm,
Here's the hot ticket:
Camber Front L +2, Front R -2
Rear L -2, Rear R +2

Have fun an I'll see you at Mid Ohio in April
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

PS Bring a rake for the gravel traps

Alan C.

 

Alan,
+2 on the left front and right rear??
Have you checked tire temps w/ this set up?
Curious.

 

I'm pretty sure Alan is making a joke. <img border="0" title="" alt="[Wink]" src="wink.gif" />

 

Note the "rake for the gravel traps"